Noise stress during pregnancy has been reported to be embryolethal, as well as teratogenic, in rats and mice. Although there have been few studies concerning the possible effects of prenatal noise stress on the development of neuro-behavioral functioning of the offspring, it is known that a combination of light and heat stress has been reported to cause changes in catecholamine levels in brain areas affecting sexual differentiation of adult rats exposed as fetuses and to cause demasculinization of male offspring. The purpose of this experiment is to determine the effects of prenatal noise stress on selected tests of neurological functioning and reactivity. The results of these experiments might be used in the planning of future studies that (1) compare the effects of noise stress to other stressers (2) measure those changes in neurochemical and neuroendocrinological status in stress exposed animals that may be correlated with any behavioral changes.